A nice model , i have a couple things that jump out at me that you might want to look at .Firstly on the side you have a balcony but there doesnt seem to be any access to it so not sure what its purpose is. Second are those wondows above the balcony ? if so they dont seem to be transparent and also im not sure they should be arched but maybe round if you are going for an express train look .
This is just a preference thing but i think the down pipe on the right should be a slightly smaller diameter.
A good model though ..i like it .